Cable-operated doors such as garage doors are well known in the art. A garage door is usually connected to an overhead counterbalancing mechanism that provides a counterbalancing force in order to decrease the force required to open the door and also facilitate its closing. A conventional garage door is typically connected to the counterbalancing mechanism by means of two cables, one at the right and one at the left. The cables are usually made of steel. The lower free end of each cable is usually attached at the bottom of the door.
It is also known in the art that a garage door needs to have a proper counterbalancing system so that it may be easily opened and closed. The counterbalancing force is generally achieved by the usage of either one or many torsional springs. Each torsional spring is generally connected to two plugs, a first one being the “winding plug” at one end of the spring, and a second one being the “stationary plug” at the other end of the spring. The winding plug is generally in turn fixed onto the shaft while the stationary plug is generally fixed onto a fixed structure, such as a bearing plate mounted to a wall for example. To transmit the force to the door, there are generally two drums on the shaft of the counterbalancing mechanism on which cables are installed. The extremities of these cables are generally fixed onto bottom brackets, one on each side (left and right) of the door, typically at the last panel of a sectional door for example.
One could envisage that although very unlikely, it might happen that one of the elements (e.g. spring) of the counterbalancing system undergoes a failure, leading to the garage door falling which is undesirable. There have been many attempts to come up with devices used for such an event.
Known in the art are the following US patents and foreign patent applications which describe various cable failure devices for garage doors and the like:
U.S. Pat. No. 6,279,268 B1; U.S. Pat. No. 6,189,266 B1; U.S. Pat. No. 6,042,158; U.S. Pat. No. 5,791,686; U.S. Pat. No. 5,704,166; U.S. Pat. No. 5,291,686; U.S. Pat. No. 4,956,938; U.S. Pat. No. 4,604,828; U.S. Pat. No. 4,385,471; U.S. Pat. No. 2,185,828; EP 721043 A1; EP 678641 A1; EP 172351 A1; EP 149692 A1; DE 3800789 A1; DE 3710237 A1; and FR 2758157 A1.
However, some of the devices taught in the above-mentioned documents are known to be fairly bulky; difficult to install, use, and/or maintain; expensive to manufacture and/or assemble; and generally not offering optimal efficiency for stopping downward movement of a cable-operated door, such as garage doors and the like, in the event of a failure of one of the cables holding such cable-operated door or in the event of a failure of one of the elements holding the cables. Moreover, most of the devices taught in the above-mentioned documents are not provided with additional safety features designed to prevent a user from tampering with and/or removing the device from the door when there is still tension in the cable, and thus prevent the user from being subject to undesirable effects as a result of substantial tension being still present in the cables.
Hence, in light of the above-discussed, there is a need for an improved cable failure device which would be able to overcome some of the aforementioned prior art problems.